vCenter Server Appliance v6.0 Upgrade Login Issue

So today I ran across an interesting issue after deciding to upgrade the vCenter Server Appliance in my lab environment. After applying the upgrade patches it seems that I was having trouble logging into the Web Client with any credentials. It didn’t seem to matter what credentials were used. Every time I would attempt to login I would receive an error that stated:

Username and password are required.

This was very odd…so here is what I did that seem to clear the issue.

1. Cleared my browsing history.
2. Removed the certificate for the vCenter from my local machine. (I did this because I was using a self-signed cert)
3. Opened a new tab in my browser and connected to the vSphere Web Client.

Odd behavior and somewhat bothersome fix. What was weird to me is I tried just clearing my browser history and that didn’t seem to fix it. It only worked once I removed the accepted self-signed certificate. Just wanted to note this in case someone else ran into the same issue. Hope this helps!